Virtual reality is typically achieved in the visual domain through the use of graphical displays that occlude a user's view of the surrounding physical environment. Head-mounted display (HMD) devices utilizing fully occluding near-eye graphical displays may be used to provide a fully immersive virtual reality experience. HMD devices may include a forward-facing camera that captures the surrounding physical environment from the viewpoint of the user. The forward-facing camera and other on-board sensors enables the positioning of the HMD device to be tracked within the physical environment, which may be mapped to a virtual viewpoint for the user in a virtual environment.